1. Field of the Invention
The invention relates to a device for the electrical connection of at least two structural elements, preferably of annular shape, which are arranged on a common axis and are rotatable with respect to each other.
2. Description of the Prior Art
At a known rotating electrical contact (German Gebrauchsmuster Pat. No. 72 04 100) an antifriction bearing is provided, whose inner ring and outer ring each have an electrical connection, the antifriction bearing is axially loaded and its inner ring at the bore-side and its outer ring at its circumference are provided with an electrically insulating layer. The rolling elements which are made of an electrically conducting material, in the form of balls retained in a cage, are in contact at one side with an inner ring having an essentially axial running track, and at the other side contact an outer ring which is also provided with an essentially axial running-ring. Due to the axial force which acts obliquely through the bearing, a reliable contact is established between all rolling elements and the two metallic tracks, so that a transfer of electric current is assured at all times. By generating an axial force in this manner, additional provisions are not required to keep the two bearings in contact with the rolling elements. The intimate contact between the mentioned parts of the electrical connecting device resulting in low transfer resistances, is thereby dependent on the presence of a force in the axial direction which, however, is not available in many cases or only present temporarily. The result is that, at least temporarily, very high transfer resistances exist due to a poor contact closure so that the application of the known device is not suitable, for example, in such cases where only a very small current of a few m.sup.A flows through the contact parts, such as for control purposes. Such a case exists at a safety system in a motor vehicle wherein an inflatable bag is disposed at the steering wheel, whose inflation-ignition mechanism is electrically activated, and must be in connection with a chassis-fixed crash-sensor through electrical connecting lines. Here, the operating reliability of the safety system must at all times be assured.